| Tóm tắt: | Tl1Ba2Ca2Cu3Ox thin films, with and without Bi-substitution, have been fabricated by in-situ laser ablation on (001) SrTiO3 and (001) LaAlO3 substrates. Using transmission electron microscopy and allied techniques, the films have been characterised in cross-section. In the case of films grown without Bi-substitution, heavily defected microstructures with a-axis oriented grains and stacking-type planar defects resulting in discontinuous a-b planes have been observed. Films fabricated with Bi-substitution have highly defected micro structure s within about 150 nm of the substrate, with considerably less faulting further from the substrate where the bulk of the superconducting currents flow and the microwave properties are primarily determined. Bi-substituted films have been fabricated with critical current density values up to 8 X 105 A cm-2 (77 K) and surface resistances values as low as 56 mΩ (77 K, 87 GHz), which is equivalent to 0.74 mΩ at 10 GHz, assuming a frequency-squared relationship. © 1998 Elsevier Science B.V. All rights reserved.
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